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Subject[PATCH v4 2/6] mtd: spi-nor: cadence-quadspi: add a delay in write sequence
Date
As per 66AK2G02 TRM[1] SPRUHY8F section 11.15.5.3 Indirect Access
Controller programming sequence, a delay equal to couple of QSPI master
clock(~5ns) is required after setting CQSPI_REG_INDIRECTWR_START bit and
writing data to the flash. Introduce a quirk flag CQSPI_NEEDS_WR_DELAY
to handle this and set this flag for TI 66AK2G SoC.

[1]http://www.ti.com/lit/ug/spruhy8f/spruhy8f.pdf

Signed-off-by: Vignesh R <vigneshr@ti.com>
---
drivers/mtd/spi-nor/cadence-quadspi.c | 27 ++++++++++++++++++++++++++-
1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c
index 53c7d8e0327a..5cd5d6f7303f 100644
--- a/drivers/mtd/spi-nor/cadence-quadspi.c
+++ b/drivers/mtd/spi-nor/cadence-quadspi.c
@@ -38,6 +38,9 @@
#define CQSPI_NAME "cadence-qspi"
#define CQSPI_MAX_CHIPSELECT 16

+/* Quirks */
+#define CQSPI_NEEDS_WR_DELAY BIT(0)
+
struct cqspi_st;

struct cqspi_flash_pdata {
@@ -76,6 +79,7 @@ struct cqspi_st {
u32 fifo_depth;
u32 fifo_width;
u32 trigger_address;
+ u32 wr_delay;
struct cqspi_flash_pdata f_pdata[CQSPI_MAX_CHIPSELECT];
};

@@ -608,6 +612,15 @@ static int cqspi_indirect_write_execute(struct spi_nor *nor,
reinit_completion(&cqspi->transfer_complete);
writel(CQSPI_REG_INDIRECTWR_START_MASK,
reg_base + CQSPI_REG_INDIRECTWR);
+ /*
+ * As per 66AK2G02 TRM SPRUHY8F section 11.15.5.3 Indirect Access
+ * Controller programming sequence, couple of cycles of
+ * QSPI_REF_CLK delay is required for the above bit to
+ * be internally synchronized by the QSPI module. Provide 5
+ * cycles of delay.
+ */
+ if (cqspi->wr_delay)
+ ndelay(cqspi->wr_delay);

while (remaining > 0) {
write_bytes = remaining > page_size ? page_size : remaining;
@@ -1156,6 +1169,7 @@ static int cqspi_probe(struct platform_device *pdev)
struct cqspi_st *cqspi;
struct resource *res;
struct resource *res_ahb;
+ unsigned long data;
int ret;
int irq;

@@ -1213,6 +1227,10 @@ static int cqspi_probe(struct platform_device *pdev)
}

cqspi->master_ref_clk_hz = clk_get_rate(cqspi->clk);
+ data = (unsigned long)of_device_get_match_data(dev);
+ if (data & CQSPI_NEEDS_WR_DELAY)
+ cqspi->wr_delay = 5 * DIV_ROUND_UP(NSEC_PER_SEC,
+ cqspi->master_ref_clk_hz);

ret = devm_request_irq(dev, irq, cqspi_irq_handler, 0,
pdev->name, cqspi);
@@ -1284,7 +1302,14 @@ static const struct dev_pm_ops cqspi__dev_pm_ops = {
#endif

static const struct of_device_id cqspi_dt_ids[] = {
- {.compatible = "cdns,qspi-nor",},
+ {
+ .compatible = "cdns,qspi-nor",
+ .data = (void *)0,
+ },
+ {
+ .compatible = "ti,k2g-qspi",
+ .data = (void *)CQSPI_NEEDS_WR_DELAY,
+ },
{ /* end of table */ }
};

--
2.14.1
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